For those of you that aren't familiar with this impressive energy efficiency initiative, here’s a quick review of the program: The LEAN Benchmarking Inventory is a three-year project funded by Massachusetts’s utility providers. The scope of the project is incredibly ambitious: the inventory will determine the energy intensity scores of 75% of the multifamily affordable housing in Massachusetts, about 13,532 buildings or 108,256 units.

One of the primary reasons for completing an inventory of this type is to develop an energy efficiency standard for this under-served sector of the built environment. How do these types of buildings perform compared to market rate housing? To efficient properties? And more importantly, what could usage be reasonably reduced to through weatherization measures?

What do the benchmarks look like?

Below are sets of benchmarks from the actual report. The gas benchmark was calculated by dividing Annual Therms by Conditioned Square footage. The buildings included in this benchmark use gas for both space heating and domestic hot water production.

For electricity, there are three different types of benchmark: a whole building benchmark, which excludes buildings that use electricity for heating, a common area benchmark for buildings where a whole building usage number was unattainable, and finally a separate whole building benchmark for buildings that use electric for heating and hot water. All three electric benchmarks are delivered in Annual kWh/Gross Square Footage.

How do these properties compare to others?

What you can't necessarily tell from those numbers is how poorly this group of buildings is performing relative to market rate and efficient housing. Here's a graph created from our database, which demonstrates the difference in energy usage. According to this graph, the "Most Efficient" threshold for Affordable Housing lies outside of the median usage for Market Rate housing.

In summary, the buildings that fall into the "Poor" category in the inventory could really use some retrofit funding.

What could be saved?

What is most significant about this inventory is the amount energy savings that would occur if each building that fell into the "Poor" category was improved to function just to the level of the buildings with median energy usage.